1. Field of the Invention
The present invention relates to a document image processing device for regenerating a document image by merging a plurality of document images read by scanners, etc., a document image merging method, and a storage medium recording a program for merging document images.
2. Description of the Related Art
There is a demand for reading an image of a large size in a newspaper, a design drawing, etc. In such a case, it is possible to use an image reading device having a scanner which can directly read an image of a large size such as an A1 size, etc. However, a large-sized image reading device not only costs high, but also requires wide installation space.
Therefore, a method with which an image of, for example, a size larger than A4 is partitioned and read by using an A4-sized scanner, and an operator manually merges the partitioned images while viewing them on a screen, or a method with which alignment marks are put on a manuscript or a transparent sheet to cover a manuscript, and a plurality of partitioned and read images are merged by using the alignment marks is proposed.
For example, the Japanese Laid-open Patent Publication (TOKKAIHEI) No. 1-229559 recites a technique with which marks instructing to partition a manuscript larger than a maximum allowable size which can be read by a single read operation into regions smaller than the maximum allowable size, are put on a manuscript beforehand, the image is partitioned into a plurality of regions so that the regions include the partition instruction marks, and the partitioned images are merged into one image based on the positional information of the partition instruction marks.
FIG. 34 explains a conventional method for partitioning and reading an image on which marks are put beforehand, and for merging the read images into the original image.
In this example, marks for merging partitioned images are put on an image to be input beforehand, a first image being the left side of the image to be input is read to include the marks during first scanning, and a second image being the right side of the image is read to include the marks during second scanning in a similar manner. Then, the positions of the marks of the first and the second images are detected, and the two images are merged so that the positions of the marks are aligned. As a result, the original image can be restored.
Recently, a small-sized hand-held scanner, which is handy to carry and is available to a notebook computer, has been developed and put into a product with the popularization of a portable notebook computer. Since a hand-held scanner of this type adopts a small-sized photoelectric conversion sensor in order to reduce the size of its main body, the width that can be scanned at one time is narrow. Accordingly, it is necessary to dividedly scan, for example, even an A4-sized manuscript a plural number of times, and to merge the read images.
However, there is a problem in that the operations of the method with which an operator manually merges images which are read by a scanner are bothersome. Additionally, since marks must be put on an image to be input whenever reading an image with the method putting marks on an image to be input, this method is difficult to use.